Body Control Module (BCM) is equipped with a self
diagnostic system which detects system failures or
abnormalities. When a malfunction occurs, BCM will store a numerical code. Malfunctions are recorded as
history or current failures. Intermittent failures may be caused by problems with electrical circuit. If a visual
inspection does not locate problem, vehicle may be driven with a DVOM attached to suspect circuit. Abnormal
voltage or resistance readings when problem occurs indicates problem is within that circuit. However, a
damaged Electronic Variable Orifice (EVO)/Passlock module can occasionally be the cause.
RETRIEVING DIAGNOSTIC TROUBLE CODES
1. Turn ignition switch to RUN position to disarm theft deterrent system (if equipped). Turn ignition switch
to OFF position. Remove RADIO fuse No. 17 (25-amp) from instrument panel fuse block. See
COMPONENT LOCATIONS .
2. Turn ignition switch to ACC position. Chime will sound 2 times to verify system has entered
programming mode for customizing special features. Within 5 seconds, turn ignition switch to OFF
position, then back to ACC position. Chime will sound 3 times to verify diagnostic mode has now been
entered.
3. BCM will begin to flash codes on SECURITY indicator light 4 seconds after entering diagnostic mode.
Each flash of indicator represents a number (i.e., one flash followed by 2 quick flashes represents DTC
12). DTC 12 will always be the first code displayed, indicating diagnostic mode is at beginning of code
display. Last code to be displayed will be DTC 55 followed by hardware configuration, then software
configuration. Each code is displayed 3 times before next code is displayed.
4. If more than one code is present, codes will display in numerical order. Codes will cycle sequentially
until diagnostic mode is exited.
BCM DTC DEFINITIONS
NOTE: DTCs 41-45 will only set while in Body Control Module (BCM) diagnostic mode
and a button on remote keyless entry system transmitter is pressed. Codes are
used to determine performance of Remote Keyless Entry (RKE) system
transmitter and receiver in BCM.
DTC Description
12 Diagnostic System Check
21/31 Courtesy Lights Feed Circuit Shorted To Ground
22/32 Courtesy Lights Return Circuit Shorted To Battery
23/33 Retained Accessory Power (RAP) Circuit Shorted To Ground Or Battery
24/34 Fasten Seat Belt Indicator Circuit Shorted To Ground Or Battery
25/35 SECURITY Indicator Light Status
41
(1)
Last Transmitter Message Received Valid
42
(1)
Last Transmitter Message Received Invalid
43
(1)
Last Transmitter Message Received Had Sumcheck Error
44
(1)
Last Transmitter Message Received Had Encryption Error
45
(1)
Receiver Processing Currently In 20-Second Lock-Out
55 Begin Configuration Display
2000 Cadillac Escalade
2000 ACCESSORIES & EQUIPMENT' 'Body Control Modules - Escalade, Tahoe & Yukon Denali
Microsoft
October-22-10 7:55:08 PM Page 5 ©
2005 Mitchell Repair Information Company, LLC.
